Typewriter erasure mechanism



Sept. 6, 1966 R. FONDILLER 3,270,352

TYPEWRITER ERASURE MECHANISM Filed Feb. 4, 1963 5 Sheets-Sheet 1 M/l/E/VTOR By ROBERT FOND/LLER K6 vrgazk A T TOPNE V Sept. 6', 1966 R. FONDILLER 3,270,852

TYPEWRITER ERASURE MECHANISM Filed Feb. 4, 1963 5 Sheets-Sheet 2 FIG. 2

//\/l/E/VTO/-? B ROBERT FUND/LLB? A 7' TOPNEV Sept. 6, 1966 R. FONDILLER TYPEWRITER ERASURE MECHANISM 5 Sheets-Sheec 5 Filed Feb. 4, 1963 ATTORNEY United States Patent 3,270,852 TYPEWRITER ERASURE MECHANISM Robert Fondiller, 33 W. 63rd St., New York 23, N.Y. Filed Feb. 4, 1963, Ser. No. 255,966 Claims. (Cl. 197-91) This invention relates to back spacing mechanisms for typewriters and, more particularly to typewriter back spacing mechanisms suitable for cooperation with ribbon shift mechanisms to provide erasure of an incorrectly typed character.

A broad object of this invention is to provide an improved typewriter back spacing mechanism.

The erasure of incorrectly typed characters may be readily accomplished by a typewriter ribbon provided with the conventional upper inked portion and a lower erasure portion which effects erasure when interposed between the character to be erased and the key face of the incorrect character. To effect the erasure operation, the ribbon is positioned by operating the ribbon shift mechanism, the carriage rack is back spaced to align the incorrectly typed character and the character key is operated. The character is generally not erased, however, by one key operation, requiring repetitive operations of the character key. Since the operation of the back space key necessarily drives the carriage rack beyond the proper alignment, to provide for backlash, the back space key must be operated and released for each character key operation.

Another object of this invention is to eliminate successive operations of a back space key.

A further object of this invention is to eliminate separate operations of the back space key and the ribbon shift key.

A feature of this invention is a linkage to operate the ribbon shift mechanism upon the operation of the back space mechanism.

It is another feature of this invention that the back space mechanism permits the carriage rack to relax after a back space operation to the proper character alignment while maintaining the carriage rack locked to preclude spacing with each operation of the typing key.

The means for fulfilling the foregoing objects and practical embodiments of the features of this invention will be fully understood from the following description taken in conjunction with the accompanying drawing wherein:

FIG. 1 shows a perspective view of one embodiment of a typewriter mechanism in accordance with this invention,

FIG. 2 illustrates a perspective view of another embodiment of the invention,

FIG. 3 shows a ribbon vibrator and typing ribbon suitable for use with this invention,

FIG. 4 shows a ribbon shift mechanism suitable for use with this invention, and

FIG. 5 shows a portion of the mechanism illustrated in FIG. 2.

Referring now to FIG. 1, a back space key is indicated by numeral 2. Connected to back space key 2 and extending below is back space key shaft 4. Back space key shaft 4 extends through a slot in latch 3 and is pivotally connected to T lever 7 by pivot pin 6. The forward edge of back space key shaft 4 is provided with notch 5. In addition, the lowest portion of back space key shaft 4 terminates in projection ear 8 which curves under T lever 7. Projection ear 8, in turn, is connected to T lever 7 by spring 9. It is thus seen that back space key shaft 4 is rotated in a clockwise direction, as viewed in FIG. 1, by spring 9 until projection ear 8 abuts against the lower surface of T lever 7. This maintains back space key shaft 4 in substantially a vertical position.

T lever 7 is pivotally mounted on pivot pin 12 and pivot pin 12, in turn, is integrally connected to typewriter frame 1. In addition, T lever 7 is provided with slot 29 to hold spring 10'. The other end of spring 10 is connected to fulcrum wire 11. With fulcrum wire 11 integrally connected to frame 1, T lever 7 is normally urged in a counter-clockwise direction about pivot pin 12. This, in turn, maintains back space key shaft in a raised position in the normal rest condition.

Back space connecting arm 16 is pivotally connected at 15 to T lever 7. Cam lever 17 is pivotally connected to back space connecting arm 16, in turn, by pivot pin 18. Cam lever 17 is mounted on pivot pin 19 which, in turn, is integrally connected to frame 1 (by means not shown). Cam lever 17 has provided therein cam slot 20. Back space wire 21 passes through cam slot 20. In the initial condition, prior to the depression of back space key 2, back space wire 21 is in the extreme left portion of cam slot 20, as viewed in FIG. 1. Back space wire 21 passes through a slot in back space wire support 22 and a slot in back space wire support bracket 23. In addition, back space wire 21 passes through slot 28 in spring 27 and spring 27 is affixed to back space wire support bracket 23, as shown in FIG. 1. Prior to the depression of back space key 2, terminal 25 of back space wire 21 rests immediately below the interval between two teeth such as interval 26 of carriage rack 24.

Assuming now that back space key 2 is depressed, back space key shaft 4 is driven downward, rotating T lever 7 in a clockwise direction, as viewed in FIG. 1. This urges back space connecting arm 16 to the left, whereby cam lever 17 is rotated in a counter-clockwise direction, as viewed in FIG. 1. Upon the initial rotation of cam lever 17, back space wire 21 is rotated in a counterclockwise direction, whereby terminal 25 is raised into interval 26 of carriage rack 24, as indicated by the dashed lines. During this initial portion of the rotation of cam lever 17, back space wire 21 rides along the surface of slot 20 to the right-hand portion. When back space wire 21 reaches the end of the right-hand portion of slot 20, back space wire 21 is moved to the left, as viewed in FIG. 1, whereby terminal 25, which now engages the teeth of carriage rack 24, urges carriage rack 24 to the left.

Carriage rack 24 is normally urged to the right by resilient means (not shown) in a manner well known in the typewriter art. In addition, as is well known in the art, the operation of the back space mechanism moves carriage rack 24 one character space interval plus an overtravel portion in order to allow for the backlash of the pinion and its ratchet in the carriage escapement. Thus, the operation of back space key 2 moves carriage rack 24 to the left one space plus an overtravel portion allowing for the backlash of the carriage rack to the appropriate space position when back space key 2 is returned to its normal rest position.

Latch 3 and shaft notch 5 on back space key shaft 4 are provided to permit carriage rack 24 to relax to its normal position while holding back space key 2 in a depressed position and maintaining terminal 25 of back space wire 21 in interval 26 between the keys of carriage rack 24, thereby precluding further movement of carniage rack 24. This is accomplished by forcing back space key 2 to the left, as viewed in FIG. 1, after it has been depressed. When back space key 2 is returned upward, shaft notch 5 catches on the under portion of latch 3, precluding the further upward movement of back space key 2. The position of shaft notch 5 relative to latch 3 is arranged to stop the upward movement of back space key 2 at the point where carriage rack 24 relaxes to the normal rest position. This corresponds to the point in the operation of the back space mechanism wherein terminal 25 was rotated into interval 26 and moved to the left approximately one character space prior to moving carriage rack 24 the additional overtravel portion. In addition, since back space wire 21 is not rotated back under carriage rack 24, terminal 25 is maintained in interval 26 precluding subsequent advancement of carriage rack 24.

The erase key assembly also contemplates that the typewriter ribbon will be shifted upon the operation of back space key 2. In conventional typewriters a ribbon shift key such as key 35 is provided. Extending from ribbon shift key 35 is shift key shaft 36 which includes lever portion 37 and lever arm 47. Lever 37 is provided with slot 42 for holding spring 41. The other end of spring 41 is connected to fulcrum wire 11 whereby ribbon shift key 35 is normally urged to the right, as viewed in FIG. 1. Lever extension 43 is pivotally connected to lever 47 at pivot 44. Shaft 46 extends through a slot in lever extension 43 and is connected to terminal 45 which is keyed to lever extension 43. Shaft 46 is also pivotally supported by frame 1.

In the initial rest position, shift key 35 is urged to the right by spring 41, as previously described. When ribbon shift key 35 is pushed to the left, lever 37 is urged to the left, as viewed in FIG. 1. Lever extension 43 is thus rotated about shaft 46 in a counter-clockwise direction, as viewed in FIG. 1. Since shaft 46 is connected to lever 43 by terminal 45, shaft 46 is similarly rotated in a counter-clockwise direction.

It is noted that fulcrum wire 11 passes through slot 39 in lever 37. The right-hand portion of slot 39, as viewed in FIG. 1, terminates in slot projection 40. Accordingly, if it is desired to hold shift key 35 in the operated position, after the key has been urged to the left, shift key 35 is merely raised to permit fulcrum wire 11. to engage slot projection 40. Shift key 35 can thereafter be released by being lowered to disengage fulcrum wire 11 from slot projection 40 whereby spring 41 will again be enabled to urge shift key 35 to the right, as viewed in FIG. 1, to the normal rest position.

As seen in FIG. 4, shaft 46 extends to the ribbon shift actuating mechanism, generally indicated by 55. Ribbon shift actuating mechanism 55 is well known in the art and may include actuating arm 56. Actuating arm 56, in turn, engages pin 57 which is connected to ribbon vibrator 58. Ribbon 59 is normally threaded through ribbon vibrator 58 in a conventional manner such as shown in FIG. 3 and FIG. 4.

As seen in FIG. 3, ribbon 59 includes an upper portion 60 and a lower portion 61. In a normal rest position, upper portion 60 is normally interposed between paper 62 and the type face (not shown) of an operated type key. In the embodiment shown in FIG. 3 and FIG. 4, ribbon 59 preferably comprises commercially-available ribbons wherein portion 60 is a normal typing portion and lower portion 61 is an erasure portion. This erasure portion may include a chalk substance on the surface thereof adjacent to paper 62 or may be impregnated with appropriate chemicals.

Returning now to the operation of shift key 35, it is recalled that shaft 46 is rotated in a counter-clockwise direction, as viewed in FIG. 1. The rotation of shaft 46, accordingly, urges actuating arm 56 upward, as viewed in FIG. 4. This, in turn, urges ribbon vibrator 58 upward, whereby erasure portion 61 is interposed between paper 62 and the type face. Accordingly, the operation of shift key 35 raises vibrator 58 to place erasure portion 61 of ribbon 59 in the appropriate position for erasing a character on paper 62.

Recalling now that the depression of back space key 2 urges back space connecting arm 16 to the left, as viewed in FIG. 1, it is noted that back space connecting arm 16 has provided therein slot 48. Lever arm 47 extends through slot 48 resting in the right-hand portion as viewed in FIG, 1.- Accordingly, when back space connecting arm 16 is urged to the left by the depression of back space key 2, lever arm 47 is similarly urged to the left, moving, in turn, lever 37. As previously described, the movement of lever 37 to the left rotates shaft 46 in a counter-clockwise direction, whereby ribbon vibrator 58 is raised. It is thus seen that the depression of back space key 2 raises ribbon 59 to the appropriate position for erasure.

Assuming that it is desired to erase a particular character, back space key 2 is depressed, moving carriage rack 24 to the left, as previously described, and raising ribbon vibrator 58 to interpose erasure portion 61 of ribbon 59. Back space key 2 is then urged to the left and raised slightly to permit notch 5 to engage latch 3.

This results in back spacing the carriage rack to the,

character space to be erased, permitting the carriage rack to relax to the normal space position and holding the carriage rack to preclude further spacing, as previously described. In addition, the slight movement upward of back space key 2 prior to the engagement of notch 5 with latch 3 is insutficient to permit vibrator 58 to return to its normal position. Accordingly, the carriage rack is held in a fixed position and the ribbon is maintained in a shifted position whereby the operation of the type key depressed in error one or more times urges portion 61 of ribbon 59 to the character typed in error on paper 62.

In the embodiment shown in FIG. 2 the back space mechanism provides for the relaxation of carriage rack 24 to the normal rest position during the downward depression of back space key 2. As previously described, the depression of back space key 2 urges a back space key shaft such as back space key shaft 4' downward, as viewed in FIG. 2. This, in turn, rotates T lever 7 in a clockwise direction about pivot pin 12. Conversely, in the normal rest position T lever 7 is urged in a counter-clockwise direction by spring 10 which is connected to fulcrum wire 11.

As previously disclosed, back space connecting arm 16 is pivotally connected at 15 to T lever 7. The other end of back space connecting arm 16 is integrally connected to pivot pin 18 which, in turn, extends through slot 63 in cam lever 17. Slot 63, as can be seen in FIG. 2 and FIG. 5, comprises a C-shape having a first end portion 64, a second end portion 65 and an interconnecting cam surface 66.

In the normal rest position with T lever 7' urged in a counter-clockwise direction, as previously described, back space connecting arm 16 is moved to the right to a normal rest position.

In this position, pivot pin 18 rests in portion 64 of slot 63 urging cam lever 17 in a clockwise direction about pivot pin 19. This rotates back space wire 21 in a clockwise direction, as viewed in FIG. 2, whereby back space wire terminal 25 rests below interval 26 provided by the teeth of carriage rack 24.

Assuming now that back space key 2 is depressed, back space key shaft 4' is driven downward, rotating T lever 7 in a clockwise direction, as previously described. This urges back space connecting arm 16 to the left, whereby cam lever 17 is rotated in a counter-clockwise direction, as previously described. Accordingly, back space wire 21 rides along the surface of cam slot 20, rotating terminal 25 into interval 26. When back space wire 21 reaches the end of the right-hand portion of slot 20, back space wire 21 is moved to the left, whereby terminal 25 urges carriage rack 24 to the left a character space interval plus an overtravel portion.

As previously described, the operation of the back space mechanism moves carriage rack 24 one character space position plus an overtravel portion. Cam lever 17"at this time has rotated a sufficient distance in the counterclockwise direction to turn surface 66 to a position substantially parallel to the direction of the travel of back space connecting arm 16. Consequently, pivot pin 18 proceeds to slide along surface 66 and enter portion 65 of slot 63. This results in returning cam lever 17' in a clockwise direction, returning, in turn, back space wire 21 to the right an amount corresponding to the character space interval position of the carriage rack prior to its movement through the overtravel portion. Accordingly, the operation of back space key 2 rotates cam lever 17 whereby back space wire 21 moves carriage rack 24 one character space position plus the overtravel portion, whereupon pivot pin 18 slides along the surface 66 from portion 64 to portion 65 of slot 63, restoring carriage rack 24 to a rest position while maintaining terminal 25 engaged with the teeth of carriage rack 24.

The erase key assembly also includes ribbon shift key 35 which, as previously described, operates shift key shaft 36 to the left. This, as previously described, operates lever 37 to the left whereby lever extension 43 rotates in a counter-clockwise direction, similarly rotating shaft 46 in a counter-clockwise direction. Accordingly, as previously described, ribbon shift actuating mechanism 55 raises vibrator 58 to interpose erase portion 61 of ribbon 59.

Recalling now that the depression of back space key 2 urges back space connecting arm 16 to the left, as viewed in FIG. 2, and back space connection arm 16 has provided therein slot 48, whereby lever arm 47 which extends through slot 48 is similarly moved to the left. Accordingly, lever 37 is moved to the left, as previously described, rotating shaft 46 in a counter-clockwise direction, whereby ribbon vibrator 58 is raised. It is thus seen that the depression of back space key 2, as seen in FIG. 2, similarly affects the shifting of ribbon 59.

Assuming that it is desired to erase a particular character with the erase key assembly shown in FIG. 2, back space key 2 is depressed, moving carriage rack 24 to the left, and thereafter permitting carriage rack 24 to relax to the normal rest position, and simultaneously raising ribbon vibrator 58 to interpose erasure portion 61, as previously described. Accordingly, the carriage rack is held in a fixed position and the ribbon is maintained in a shifted position. Therefore, maintaining back space key 2 depressed permits the multiple operation of the type key of the character typed in error to affect the erasure of the character.

Although a specific embodiment of this invention has been shown and described, it will be understood that various modifications may be made Without departing from the spirit of this invention and within the scope of the appended claims.

What is claimed is:

1. In a typewriter, a ribbon vibrator, mechanism for shifting said vibrator, a carriage rack, mechanism for back spacing said carriage rack, a manually operable key, a first linkage coupling said shifting mechanism to said key for rendering said shifting mechanism responsive to the operation of said key, a second linkage coupling said back spacing mechanism to said key for moving said back spacing mechanism a character space interval plus an overtravel portion in response to the operation of said key, and locking means for \maintaining said key operated, said locking means being arranged to permit the partial resetting of said key to relax said back spacing mechanism said overtravel portion.

2. In a typewriter, a manually operable key, a ribbon vibrator, mechanism for shifting said vibrator in response to the operation of said key, a carriage rack, a back spacing mechanism for sequentially engaging said carriage rack and moving said carriage rack a character space interval plus an overtravel portion in response to the operation of said key, and locking means for maintaining said key operated, said locking means being arranged to permit the partial resetting of said key to relax said back spacing mechanism to a position in said sequence prior to said overtravel portion.

3. In a typewriter, a manually operable key, a ribbon vibrator, mechanism for shifting said vibrator in response to the operation of said key, a carriage rack, a back spacing mechanism for sequentially engaging said carriage rack and moving said carriage rack a character space interval plus an overtravel portion in response to the operation of said key, and locking means for maintaining said key operated, said locking means being arranged to permit the partial resetting of said key to relax said back spacing mechanism to said character space interval in said sequence.

4. In a typewriter, a carriage rack, mechanism for back spacing said carriage rack, a manually operable key, and a linkage coupling said back spacing mechanism to said key for sequentially engaging said carriage rack and moving said carriage rack a character space interval plus an overtravel portion in response to the operation of said key, said linkage including means for relaxing said back space mechanism to said character space interval position in said sequence when said key is fully operated, said relaxing means including a slot having a first end portion and a second end portion, a pin normally positioned in said first end portion, and means for urging said pin to said second end portion when said key is fully operated.

5. In a typewriter in accordance with claim 4, including a ribbon vibrator shifting mechanism and a linkage coupling said shifting mechanism .to said manually operable key.

References Cited by the Examiner UNITED STATES PATENTS 434,991 8/1890 Merritt 19780 559,345 4/1896 Wagner et 'al. 197-155 X 921,598 5/1909 Doane 197--91 924,593 6/1909 Strong 19791 1,035,928 8/1912 Whitcomb 197-91 1,060,004 4/1913 Kavle 197-91 1,215,307 2/1917 Johnson 19791 1,684,428 9/1928 Barr 19791 2,675,110 4/1954 Yaeger 197-91 X FOREIGN PATENTS 528,589 11/ 1940 Great Britain.

ROBERT E. PULFREY, Primary Examiner.

ERNEST T. WRIGHT, Assistant Examiner. 

1. IN A TYPEWRITER, A RIBBON VIBRATOR, MECHANISM FOR SHIFTING SAID VIBRATOR, A CARRIAGE RACK, MECHANISM FOR BACK SPACING SAID CARRIAGE RACK, A MANUALLY OPERABLE KEY, A FIRST LINKAGE COUPLING SAID SHIFTING MECHANISM TO SAID KEY FOR RENDERING SAID SHIFTING MECHANISM RESPONSIVE TO THE OPERATION OF SAID KEY, A SECOND LINKAGE COUPLING SAID BACK SPACING MECHANISM A CHARACTER SPACE INTERVAL PLUS BACK SPACING MECHANISM A CHARACTER SPACE INTERVAL PLUS AN OVERTRAVEL PORTION IN RESPONSE TO THE OPERATION OF SAID KEY, AND LOCKING MEANS FOR MAINTAINING SAID KEY OPERATED, SAID LOCKING MEANS BEING ARRANGED TO PERMIT THE PARTIAL RESETTING OF SAID KEY TO RELAX SAID BACK SPACING MECHANISM SAID OVERTRAVEL PORTION. 